In the field of brush applicators there has been a longfelt need for brush heads which would allow greater amounts of paint and other materials to be loaded onto the brush without loss of precision in applying that paint or other material to the surface being worked upon.
Brushes constructed from different materials have attempted to solve this problem. Improvements over conventional long bristle or filament brushes include the development of foam brushes. Foam brushes which have a removable and replaceable foam head are well-known. In many instances, a foam head is held in place on the handle of the brush by a series of barbs on the perimeter of a section of the handle. The barbs hold the foam head onto the handle section, but may also allow selective removal of the head.
Other means of attaching foam heads to brush handles include: glue which bonds the head permanently to a handle; sonic welding of the foam head directly to the handle; as well as other methods. Preferably, a foam head is selectively removable for cleaning and/or replacement.
Various types of foam material may be used to fabricate a foam brush head. The variety of foams available include inexpensive polyether foams which swell when immersed in solvents or solvent-based paints, as well as more expensive polyester foams which are more color stable and more stable in solvents, when compared with polyethers. Ester foams are usually constructed of a web or skeleton of multihedral shaped cells joined together. A foaming process during manufacture allows a thin film of plastic to connect the perimeters of each of the planes of the cells. Also, some foam brushes are fabricated from an ester that has been reticulated. The reticulation process removes the above described plastic web leaving only the skeleton of the ester. A reticulated ester foam brush allows for a much freer flow of particles through the head of the brush making it generally more absorbent.
Although paint brushes made from foam heads represent substantial improvement over the prior art, the foam brushes also contain limitations. For example, due to the excellent absorption characteristics of advanced foam heads, paint is absorbed into the foam and is not easily released. Also, the quality or evenness of the paint which issues from a foam head brush depends to a large degree on the precision with which the leading edge of the foam head is fabricated. Typically, foam heads are used to apply enamels, urethanes, and other glossy surface liquids that, preferably, require a smooth even application. Therefore, the above disadvantages of foam heads are accentuated by the types of liquids which are commonly applied by these heads.
One method of improving the smoothing characteristics of a paint applicator is illustrated in U.S. Pat. No. 3,117,334, which issued to P. V. Imhof on Jan. 14, 1964, and wherein a piece of mohair is adhesively bonded to a plastic applicator. A similar method of applying paint is shown in U.S. Pat. No. 4,674,144, issued to Joseph Palmeri on June 23, 1987, in which the paint applicator surface includes a first layer of foam upon which a nap or field of bristles is placed. A similar technique of utilizing stiff fibers attached to an underlying foam pad is disclosed in U.S. Pat. No. 4,39l,0l3 issued to Craig R. Janssen on July 5, 1983. The fibers in the Janssen patent are attached to a finishing tool for finishing wall board tape joints and are coarse so as to function as abrasive agents in order to loosen and then smooth a surface of a tape joint. None of the above patents disclose a means for substantially improving the loading characteristics of a paint brush while simultaneously providing smoothing filaments which ensure a more precise application edge of the brush for delicate finishes.